It looks like Adobe AIR and Microsoft Silverlight are going to get some competition from Mozilla. From the announcement:

Mozilla Labs is launching a series of experiments to bridge the divide in the user experience between web applications and desktop apps and to explore new usability models as the line between traditional desktop and new web applications continues to blur.

Unlike Adobe AIR and Microsoft Silverlight, we’re not building a proprietary platform to replace the web. We think the web is a powerful and open platform for this sort of innovation, so our goal is to identify and facilitate the development of enhancements that bring the advantages of desktop apps to the web platform.

The first of these experiments is based on Webrunner, which we’ve moved into the Mozilla Labs code repository and renamed to Prism.

Prism is an application that lets users split web applications out of their browser and run them directly on their desktop.

At least for now, this doesn’t look quite as robust as Adobe AIR (and I’ve not looked at Silverlight too closely) but it does seem like a natural progression for Firefox. You have to wonder how many of these environments developers are going to embrace. I’d guess there will be a small number of players that remain standing after a shakeout. AIR and Prism both plan to support Linux, Mac OS X and Windows.

In my opinion, Adobe is near the top of the list of mainly proprietary companies that could most benefit from opening up. Their vision for RIA is compelling, but a key to platform success is ubiquity and in this day and age that’s really hard to reach without Open Source. It seem Adobe has taken a good first step by releasing Flex under the MPL. From Adobe:

Adobe is announcing plans to open source Flex under the Mozilla Public License (MPL). This includes not only the source to the ActionScript components from the Flex SDK, which have been available in source code form with the SDK since Flex 2 was released, but also includes the Java source code for the ActionScript and MXML compilers, the ActionScript debugger and the core ActionScript libraries from the SDK. The Flex SDK includes all of the components needed to create Flex applications that run in any browser – on Mac OS X, Windows, and Linux and on now on the desktop using “Apollo”.

Developers can use the Flex SDK to freely develop and deploy Flex applications using either Adobe Flex Builder or an IDE of their choice.

The source code for the Flex framework is already available within the free distribution of the current Flex 2 SDK. By this summer, Adobe plans to put in place most of the infrastructure (public bug database and public daily builds) required to run the Flex SDK as an open source project. We expect to complete the transition to a fully open source project (source code for the compiler, infrastructure for community contributions, etc.) by the end of 2007.

It should be noted that Linux, Solaris and Max OS X are all on the list of supported platforms. Some may say that this isn’t really big news. After all, it’s not like they are MPL’ing Flash. The thing is, Adobe is a large and established company. You can’t expect them to change overnight. This is a good first step. Hopefully there will be solid next steps. The web is almost certainly the next platform. It needs to be open. I think Adobe gets that.